On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.

- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P

- You mention the recommended above, based on diminishing returns, but
what insulation material is that based on - as I understand it, different
manufacturers produce insulation to different values. So my thought was,
that maybe 200mm of rockwool, might equal 300mm of crown or something?

Thanks again

Dean